Bromine
. Bromine, symbol Br, poisonous element that at room temperature is a dark, reddish-brown liquid. In group 17 (or VIIa) of the periodic table , bromine is one of the halogens . The atomic number of bromine is 35. Bromine is widely distributed in nature. It melts at -7.25° C (18.95° F), boils at 58.78° C (137.8° F), and has a specific gravity of 3.10; the atomic weight of the element is 79.90. Bromine is so similar in its chemical properties to chlorine , with which it is almost invariably associated, that it was not recognized as a separate element until 1826, when it was discovered and isolated by the French chemist Antoine Jérôme Balard. Bromine is very soluble in a wide variety of organic solvents, such as alcohol , ether , chloroform , and carbon disulfide . It reacts chemically with many compounds and metallic elements and is slightly less active than chlorine. Bromine does not occur in nature as a free element, but is found in bromide compounds. It was formerly a by-product of th